Nucleic acids such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are used extensively in the field of molecular biology for research and clinical analyses. RNA may be found in nature in various forms, including messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), and viral RNA. Each of these types of RNA has distinct properties related to their specific functions. Analysis of RNA expression levels and patterns provides important information in fields such as developmental genetics, drug discovery and clinical diagnostics. For example, RNA analysis provides important diagnostic information about both normal and aberrant functioning of genes. Furthermore, gross DNA rearrangements associated with common leukemias are detected by isolation and identification of abnormal, hybrid RNAs.
Common methods for analyzing RNA include northern blotting, ribonuclease protection assays (RPAs), reverse transcriptase-polymerase chain reaction (RT-PCR), cDNA preparation for cloning, in vitro translation and microarray analyses. To obtain valid and consistent results from these analyses, it is important that the RNA be purified from other components common to biological materials such as proteins, carbohydrates, lipids and DNA.